/**
 * #      451
 * 名称   根据字符出现频率排序
 * 链接   https://leetcode-cn.com/problems/sort-characters-by-frequency
 * 题解   [449](https://leetcode-cn.com/problems/sort-characters-by-frequency/solution)
 * 通过率 66.8%
 * 难道   中等
 */

